The present invention generally relates to a gluing machine, and more specifically to a pivotally mounted glue dispensing tray which permits glue in a relatively large reservoir to be gradually released to an open trough for application to a pickup roller and which tray is pivotally movable from an operative to a glue filling position which additionally exposes the rollers of the gluing machine for cleaning.
The improved glue supply tray of the present invention may be utilized with many suitable gluing machines, or other machines which require gradual dispensation of viscous fluid.
Gluing machines generally utilize substantially open trays in which a quantity of glue is added to a sufficient level which assured at least partial immersion of a pickup roller therein. With continued operation of the gluing machine, and after a quantity of glue is removed from the tray, it becomes necessary to refill the tray. With the glue trays of the type utilized in the prior art, it has been necessary to fill the trays with glue to an excessive level to assure that the pickup roller remains immersed within the glue for a much longer period of time before replenishing glue is necessary. Clearly, the provision of a small quantity of glue which only results in minimal immersion or "kissing" of the top surface of glue is not practical since this required constant monitoring and refilling of the glue tray to maintain the necessary level for such minimal immersion.
An additional disadvantage of the conventional glue trays has been that these trays have generally been totally open and the entire supply of glue contained in the tray has been exposed to the atmosphere. This generally tended to cause relatively rapid during up or hardening of the glue within the tray. Subsequent to termination of use of the machine, for this reason, it was in many cases necessary to manually remove all the glue from the tray in order to prevent total hardening thereof which would make subsequent removal particularly difficult. Clearly, this represented considerable effort and time in the maintenance of such glue trays.
An additional disadvantage associated with many gluing machines has been the inaccessibility of the pickup as well as other rollers of the machine for cleaning. In part, this inaccessibility has resulted from the presence and position of the glue tray relative to these rollers. For this reason, it has been necessary, during cleaning the rollers, to remove the tray from the machine and, as mentioned above, to remove the glue from the tray in the process.
Because of the above-mentioned disadvantages, the cold glue trays of the prior art generally could not be left within the glue machine but had to be removed during prolonged periods of nonuse.
One example of a tray arrangement of the type discussed above is described in U.S. Pat. No. 3,204,603. As will become evident from the description that follows, the present invention makes it possible to substitute a glue dispensing tray in accordance with the present invention for the conventional tray disclosed in that patent with minimal modification of the machine.
As will become clear. the glue dispensing tray in accordance with the present invention eliminates the above described disadvantages and offers numerous advantages. Firstly, the subject dispensing tray provides substantially greater glue capacity than heretofore possible. A substantially large reservoir gradually releases sufficient quantities of glue to maintain a relatively low level of glue in an open trough. This level is sufficient for relatively small immersion of the pickup roller within the glue, the glue being slowly replaced from the reservoir at the rate at which it is picked up by the pickup roller. The tray of the present invention provides convenient means for storage of glue over extended periods of time without the glue hardening or becoming unusable. By moving the tray to its filling or non-dispensing position, and covering the opening which communicates the reservoir to the open trough, the glue may be maintained within the reservoir for extended periods of time without having to remove the glue and replace the tray as with prior art trays.
Additionally, although more glue is stored within the tray, less glue is exposed to air than with prior art trays. The reason for this is that a substantial portion of the tray is covered or in the nature of a substantially sealed reservoir, the only open portion being an open trough portion which receives the pickup roller. As suggested above, since less glue is exposed to the air, less glue becomes hardened and the glue is maintained in condition for rapid use as required.
A further advantage of the tray in accordance with the present invention is that glue within the open trough, released from the reservoir, can be maintained at a relatively low level sufficient to be "kissed" by the pickup roller. The regulation of the level of glue in the open trough and the ability to maintain the same at a relatively constant low level permits cleaner operation without getting glue into the roller bearings.